The present invention relates to a prosthetic device and a method of healing, but more specifically to an implant that produces a magnetic field in a region of surrounding tissue or bone to aid the healing process. The magnetic field interacts with calcium ions in the region of the implant in order to shorten overall healing time, retard bacterial growth, and speed up fusion of bone or tissue to an implantable base structure.
This invention is illustrated in a dental application but has application to mammalian implants generally.
As known in the art, surgical placement of medically necessary oral implants requires an osteotomy (hole) in the bone of the maxillary or mandibular alveolus jaws. Once the size of the surgical site has been achieved and accessed, a recovery or healing phase follows to allow the implants to osseous integrate or fuse the bone with a biocompatible implanted material. This process requires a certain amount of healing time, the duration of which depends on the patient's ability to heal and counter bacterial growth.
A totally magnetic implant system according to the present invention reduces healing time and can be made of, but not limited to, sintered hard ferrite/ceramic, sintered, rare earth bonded alnico, or flexible magnets and their assemblies. The inventive implant may comprise either isotropic or anisotropic properties. The ensuing magnetic and electromagnetic field will aid in the art of healing. Electric or magnetic stimulus of the tissue causes bone to heal or osseointegrate at a faster rate.
According to the present invention, techniques that promote osseointegration include increasing the surface area of the implant using, for example, acid etching or plasma spraying. A coating material such as HA (hydrorylapptite) may also be applied to the implant to assist osseointegration. Electrical or magnetic stimulus from the magnetic implant induce fibroblast to lay down fibrin (glue) which forms a bridge or scaffold between bone and the implant. The stimulus causes bone fusion of the implant (stability) in a shorter time.
If bacteria grow in the implanted region, it may either delay healing or cause total failure of the healing process. The electromagnetic or magnetic field produced by the inventive implant, on the other hand, effectively produces a bacterialcidal or bacterial static environment that retards or stops interference with the healing process.
Once the process of osseointegration is complete, a prosthetic abutment may be secured to the bone-fused implant using screws or other conventional means of anchorage. In the prior art, problems often occur when screws attached directly to bone fracture or become dislodged or unscrewed which, in turn, causes dislodging of the prosthetic abutment from the implant. Utilizing a total magnetic system according to the present invention, however, stabilizes the implant and prosthetic abutment.
European practitioners have been using medical magnetic fields for years (see Dr. William Pawluk's article, www.naturalhealthweb.com/articles/pawluk1.html). Magnetic fields provide beneficial results by electrically stimulating a mammal's immune system in the affected region.
It was not know in the past, however, to use magnetic elements for substructural and superstructural components of an implant system or to arrange magnetic components to focus a magnetic field at an interface region between an implantable base and surrounding tissue to facilitate healing or to fight bacterial infection in the implant region. Prior use of magnetic fields within the context of prosthetics was primarily limited to affixation. Some are disclosed in U.S. Pat. Nos. 4,258,705 to Sorensen et al., 5,507,835 to Jore, 4,693,686 to Sendax, 4,214,366 to Laban, 4,302,189 to Gillings, 5,611,689 and 5,425,763 to Stemmann, 6,187,041 and 2001/0046205 to Garnozik, and 6,275,736 to Kuzma. These devices employed magnets to stabilize the position of at least a portion of a prosthetic device, either by using attractive magnetic forces to bind together more securely a base implant and prosthesis or by using repulsive magnetic forces to relieve pressure the implant may impose on surrounding tissue during healing. In addition, prior techniques to aid osseointegration of surrounding tissue with the implant involved acid etching or plasma spraying to increase the surface area of the implant to which bone may fuse.
The present invention, on the other hand, provides a method or system to utilize magnetic implants to both anchor and heal; and also to establish a concentrated magnetic field in the tissue region to facilitate fusion of tissue with the implantable base. The magnetic field also establishes a retardant to bacteria that might otherwise interfere with healing and fusion.
These goals are achieved using a biocompatible material for the base substructure as well as for a prosthetic superstructure that may abut the substructure. Each component is positioned relative to the other to establish predictable magnetic fields in the tissue region.